The invention relates to a method for coding a presentation, the coded presentation comprising at least one presentation element and a play-out specification of the presentation element indicating how the presentation element is to be played out.
The invention further relates to a method for playing out a coded presentation comprising at least one presentation element, in which method the presentation element is played out according to a play-out specification.
The invention further relates to an apparatus for playing out a coded presentation, coded according to the above method for coding a presentation.
The invention further relates to an apparatus comprising a converter module for amending a coded presentation, the coded presentation comprising:                at least one presentation element, and        a play-out specification of the presentation element.        
The invention further relates to an information carrier comprising a coded presentation, which is coded according to the above method for coding a presentation.
It is known to code a presentation into a description according to a given format. The coded presentation may be transferred via a network or stored in a memory medium for subsequent play out by a suitable apparatus. An example of such a format is the ISO/IEC standard IS 13522-5, better known as MHEG. This standard is described in the document “ISO/IEC International Standard IS 13522-5 (MHEG) Information Technology—Coding of multimedia and hypermedia information, Part 5: Support for base-level interactive applications”, November 1996. The presentation may include presentation elements comprising text, audio, video or an image. A presentation element can be regarded as an elementary item that is to be presented. In MHEG, a presentation element is called a Presentable. The coded presentation may include a play-out specification for the play out of a given presentation element. An example in MHEG is where a presentation element somewhere in the presentation may cause the start of another presentation element somewhere else in the presentation. This event-action mechanism provides the author of the presentation with control over the timing of the various presentation elements. So, during play out of a coded presentation, a specific presentation element may be triggered by a running presentation element and the timing behaviour of said specific presentation element is determined on the basis of the direct relation between the running presentation element and that specific presentation element. This causes the problem that the presentation must be executed integrally and that it is very cumbersome to remove a presentation element or substitute it by another one.